IOP: Reset recompiler and map RAM mirrors on IOP soft reset

When SifIopReset triggers (SBUS_F240 bit 19), psxReset() reloads the
IOP BIOS kernel into RAM but does not flush the IOP recompiler cache.
The recompiler keeps stale compiled blocks for IOP RAM addresses that
now contain different code. When the fresh kernel executes, the
recompiler serves old translations, causing the IOP to crash on
garbage instructions (psxUNK).

Add psxCpu->Reset() after psxReset() in the SBUS_F240 handler to
flush all cached recompiler blocks. This forces fresh recompilation
from the new RAM contents, allowing IOP soft resets to complete
correctly. This fixes SifIopReset as used by ps2link and other
PS2 homebrew that perform runtime IOP resets.

Additionally, map IOP RAM mirrors throughout kuseg (pages 0x0000-
0x1DFF) in the recompiler lookup table. The PS2 IOP mirrors its
2MB RAM across the entire kuseg address space (0x00000000-
0x1DFFFFFF). The BIOS uses these mirrored addresses during IOP
soft resets (e.g. jumping to 0x0d000100 which mirrors to physical
0x00000100). Without the mirrored pages in recLUT, code execution
at mirrored addresses would hit unmapped pages.

Author: fjtrujy

pcsx2/HwWrite.cpp

@@ -178,6 +178,7 @@ void _hwWrite32( u32 mem, u32 value )
 						u64 cycle = psxRegs.cycle;
 						//pgifInit();
 						psxReset();
+						psxCpu->Reset();
 						PSXCLK =  33868800;
 						SPU2::Reset(true);
 						setPs1CDVDSpeed(cdvd.Speed);

pcsx2/x86/iR3000A.cpp

@@ -955,16 +955,23 @@ void recResetIOP()
 	// The bottom 2 bits of PC are always zero, so we <<14 to "compress"
 	// the pc indexer into it's lower common denominator.
 
-	// We're only mapping 20 pages here in 4 places.
-	// 0x80 comes from : (Ps2MemSize::IopRam / _64kb) * 4
-
-	for (int i = 0; i < 0x80; i++)
+	// Map IOP RAM with mirrors throughout kuseg (0x0000-0x1DFF).
+	// The PS2 IOP mirrors its 2MB (or 8MB) RAM across the entire kuseg
+	// address space. The BIOS uses mirrored addresses (e.g. 0x0d000100
+	// which maps to physical 0x00000100) during IOP soft resets.
 	{
-		u32 mask = (Ps2MemSize::ExposedIopRam / _64kb) - 1;
+		const u32 mask = (Ps2MemSize::ExposedIopRam / _64kb) - 1;
+
+		for (int i = 0; i < 0x1e00; i++)
+		{
+			recLUT_SetPage(psxRecLUT, psxhwLUT, recRAM, 0x0000, i, i & mask);
+		}
 
-		recLUT_SetPage(psxRecLUT, psxhwLUT, recRAM, 0x0000, i, i & mask);
-		recLUT_SetPage(psxRecLUT, psxhwLUT, recRAM, 0x8000, i, i & mask);
-		recLUT_SetPage(psxRecLUT, psxhwLUT, recRAM, 0xa000, i, i & mask);
+		for (int i = 0; i < 0x80; i++)
+		{
+			recLUT_SetPage(psxRecLUT, psxhwLUT, recRAM, 0x8000, i, i & mask);
+			recLUT_SetPage(psxRecLUT, psxhwLUT, recRAM, 0xa000, i, i & mask);
+		}
 	}
 
 	for (int i = 0x1fc0; i < 0x2000; i++)